Not applicable.
Not applicable.
The invention relates to flow control devices having one or more shiftable valve members. More particularly, the invention relates to apparatus and methods for moving a shiftable valve member from an open to a closed position.
Fluid flow operations often involve the use of flow control devices having shiftable valve members that can be opened and closed to control fluid flow thereby. Mechanisms are thus necessary to enable movement of the shiftable valve members from open to closed positions. For example, conventional oil and gas well operations commonly utilize flow control devices that can be closed to shut off fluid flow and opened to allow fluid flow thereby, or otherwise provide access into and through the flow control device. For a particular example, flapper type safety valves are commonly located in well tubing and include a flapper member movable between open and closed positions.
Mechanisms for closing flow control devices have been proposed. For example, U.S. Pat. No. 4,624,315 to Dickson et al., U.S. Pat. No. 4,411,316 to Carmody, U.S. Pat. No. 3,786,866 to Tausch et al. and U.S. Pat. No. 4,660,646 to Blizzard each discloses a spring engaged with the shiftable flapper member of a flapper type valve assembly and disposed around a hinge pin to bias the flapper member into a closed position. U.S. Pat. No. 5,137,090 to Hare et al. discloses a curved beam type spring mounted within the tubular body of a flapper valve and an arm that engages the flapper member for yieldably urging the flapper member toward its closed position. For yet another example, U.S. Pat. No. 4,531,587 to Fineberg discloses the use of a pair of helical torsion springs engaged with hinge pins which are integral to the flapper member for biasing a flapper member to its closed position.
With respect to each of the above-cited patents, it is important to understand that the features mentioned above are merely examples of features disclosed in the patents. There are numerous other features disclosed in each patent in addition to the features mentioned herein. The additional features can be readily understood from a thorough review of each respective patent. The brief discussion above is included only to introduce the subject matter of the patents and not to distinguish the same from the present invention. Therefore, it is the patent applicant""s intent that the brief remarks above about the cited patents not, in any way, limit or affect the scope of any of the appended claims. A comparison of any of the above-cited patents with the invention of any of the appended claims should involve a comparison of all features of the cited patent together as compared with the entirety of the selected claim(s).
In considering existing technology for closing the shiftable valve member of a flow control device, there remains a need for apparatus and methods having one or more of the following attributes: ensuring the shiftable valve member remains closed when in a closed position; an apparatus that is strong and reliable in the environment within which it is used; an apparatus that may be used in a dual spring configuration to provide added biasing force for yieldably urging the shiftable valve member in a closed position; an apparatus that requires or occupies minimal or no additional length in the flow control device or the conduit within which the flow control device is located.
In accordance with the present invention, certain embodiments involve an apparatus capable of moving a shiftable valve member into a closed position and retaining it in the closed position. The shiftable valve member is mounted in a valve housing having a bore and is moveable between at least one open and at least one closed position relative to the bore. A first spring assembly is engageable with the shiftable valve member, moves the shiftable valve member into a closed position and assists in retaining it in the closed position. A second spring assembly including at least one elastically deformable member that extends at least partially around the circumference of the bore and is disposed at least partially in a cavity in the valve housing. Each elastically deformable member is elongated, has first and second ends and is connected to the shiftable valve member at one location and to the valve housing at one or more other locations. Each elastically deformable member is torsionally loaded to provide biasing, closing force to the shiftable valve member to assist in moving the shiftable valve member into a closed position and retaining it in the closed position. The second spring assembly may include a single elastically deformable member connected at its first and second ends to the valve housing and therebetween to the shiftable valve member.
The second spring assembly may include first and second elastically deformable members, each of the first and second elastically deformable members connected at its first end to the shiftable valve member and at its second end to the valve housing. The elastically deformable members may be non-rigidly connected with the valve housing. The apparatus may include an arm engageable between the shiftable valve member and the elastically deformable members. The elastically deformable members may be non-rigidly connected with the shiftable valve member.
The shiftable valve member may be a flapper valve member disposed in a subsurface well conduit and the elastically deformable member may have a generally elliptical, rectangular, circular or other shaped cross section. The elastically deformable member(s) may include a plurality of wires and/or be constructed of metals, single strands of wire or composites. The apparatus may have an arm engageable between the shiftable valve member and the elastically deformable member(s).
Certain embodiments of the present invention involve a flapper valve closing device for moving a flapper valve member into a closed position and retaining it in the closed position under normal operating conditions, where the flapper valve member is disposed in a valve housing and is useful in an underground oilfield tubular. The valve housing has a bore and the flapper valve member is hingeably moveable between at least one open and at least one closed position relative to the bore. The flapper valve closing device includes an elastically deformable member extending at least partially around the circumference of the bore and disposed at least partially in a cavity formed in the valve housing. The elastically deformable member is elongated, has first and second ends, and is connected with the valve housing at its first and second ends and with the flapper valve member therebetween. The elastically deformable member is torsionally loaded to provide biasing, closing force upon the flapper valve member to move the flapper valve member into a closed position and retain the flapper valve member in the closed position during normal operating conditions.
The flapper valve closing device may include a pivotable arm assembly having at least one rotatable hinge pin and an arm engageable with the flapper valve member, the elastically deformable member being connected with the pivotable arm assembly. The elastically deformable member may be non-helical, may be non-rigidly connected with the valve housing and may have a generally elliptical cross-section, or any combination or none such features.
In certain embodiments, the present invention involves a safety valve for use in an oilfield tubular and including a housing having a longitudinal bore extending therethrough and a flapper valve member mounted in the housing. The flapper valve member is hingeably movable relative to the longitudinal bore and has an open position allowing fluid flow through the longitudinal bore and a closed position disallowing fluid flow through the longitudinal bore. The safety valve includes first and second springs engageable with the flapper valve member. The second spring includes at least one elongated elastically deformable member disposed at least partially around the circumference of the longitudinal bore. Each elongated elastically deformable member is associated with the flapper valve member at one location and with the housing at one or more other locations. The first and second springs provide biasing forces to move the flapper valve member into a closed position. The second spring may include first and second elongated elastically deformable members, each elongated elastically deformable member being connected at its first end to the flapper valve member and at its second end to the housing.
Various embodiments of the present invention involve a subsurface safety valve for use in an oilfield tubular that includes housing means having a longitudinal bore extending therethrough and shiftable valve means mounted in the housing means for allowing and disallowing fluid flow through the longitudinal bore. The shiftable valve means has an open position capable of allowing fluid flow through the longitudinal bore and a closed position capable of at least partially blocking fluid flow through the longitudinal bore. The safety valve also includes first and second spring means for urging the shiftable valve means into a closed position and retaining it in the closed position. The second spring means is elastically deformable and disposed at least partially around the circumference of the longitudinal bore.
In accordance with the present invention, certain embodiments involve a method of moving a shiftable valve member of a subsurface safety valve into a closed position with the use of a valve closing device. The shiftable valve member is disposed in a housing having a bore and the valve closing device includes at least one elongated elastically deformable member disposed at least partially around the circumference of the bore. Each elongated elastically deformable member is connected with the shiftable valve member at one location and with the housing at at least one other location. The method includes actuating the valve opening device to move the shiftable valve member out of a closed position and cause the at least one elongated elastically deformable member to twist, and releasing the valve opening device. The at least one elongated elastically deformable member will attempt to untwist, applying biasing force to the shiftable valve member to move it into a closed position and retain it in the closed position.
Accordingly, the present invention includes features and advantages which enable it to substantially advance the technology associated with moving a shiftable valve member into a closed position. Characteristics and advantages of the present invention described above, as well as additional features and benefits, will be readily apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments and referring to the accompanying drawings.